Mathematics, Folk body of traditional mathematics, originally transmitted orally. Folk mathematics may be regarded as an undercurrent to the main stream of mathematics; it nourishes the mainstream, and at the same time, is nurtured by it. Being extremely practical in nature it serves the daily need of the people of every walk of life. Common people with elementary education can apply it at ease to the solution of various problems arising out of everyday life, seek recreation in it, and are encouraged to devise new problems or puzzles orally, whether those are significant or trifling.
That several problems on folk mathematics had been current in ancient India is evident from traces that can still be found in the Bakhshali manuscript (300 AD), the Patana manuscript (775 AD), Mahavira's Ganita-sara-samgraha (850 AD) and in other works of mathematics. Even though Bangalis in general did not show much interest in the study of mathematics, a sort of mathematics contained in the Xubhamkar were most probably cultivated by the Bangalis since 300 BC. Xubhamkar literally means a book on arithmetic, which can benefit mass education. It is uncertain whether the arithmetical system was introduced by Xubhamkar during the reign of the Mallas in the first half of the 17th century. But there was certainly a mathematician, Xubhamkar by name, in medieval Bengal, who had written several rules (aryas) pertaining to mathematics in the form of folk rhymes. The language in which the rules were composed is mainly the Bengali prevalent in medieval Bengal with lots of words taken from Prakrt, Apabhramxa, Abahatta and from Austro-Asiatic languages. There were many arya authors in Bengal and Assam in medieval time whose names were mentioned at the end of several aryas.
To find the area of a plot of land in bighas, the following aryas is recommended:
Kudba kudba kudba lijje
কুড়বা কুড়বা কুড়বা লিহ্যে
kathay kudba kathay lijje
কাঠায় কুড়বা কাঠায় লিহ্যে
kathay kathay dhul pariman
কাঠায় কাঠায় ধূল পরিমাণ
bish ganda hay kathar praman
বিশ গন্ডা হয় কাঠার প্রমাণ
ganda baki thake yadi katha nile par
গন্ডা বাকি থাকে যদি কাঠা নিলে পর
solo diye pure tare sara ganda dhar
ষোল দিয়ে পুরি তারে সারা গন্ডা ধর
Translation: kudba multiplied by kudba, take it, as (square) kudba, katha by kudba as (square) katha; katha by katha as dhul, it being divided by 20 yields (square) katha; the remainder (if there be) when multiplied by 16 gives forth (square) ganda.
Interestingly, ganda and pana are Austro-Asiatic words and had been in use since 300 BC as is evident from the excavation at mahasthan garh in the district of bogra in Bangladesh. There are other positive grounds to believe that folk mathematics was prevalent in ancient time not only in India, but also in Bengal. [Nandalal Maiti]